trains are well sick
Unlike many other subway systems across the globe, the London Underground didn't have a specific start point - it sort of slowly but surely crept into existence. In the very beginning, it originated as two separate railway companies; the Metropolitan Railway, and the District Railway. Both of these lines served the city, but trains could not advance to the city centre due to the presence of many historical buildings and landmarks which made the construction of further overground railways incredibly difficult. Both of these railways would run largely overground, until it was proposed that parts could run underground. So, these parts of both lines were concealed with a method now known as 'Cut-and-Cover', where the railway is dug into a trench just below ground, before being either covered or otherwise concealed by cladding. The first truly 'underground' line was what is now the Northern Line, tunnelled in 1863 using the now widely used tunnel boring machine, invented by James Henry Greathead.
The above GIF is 1973 London Underground rolling stock, in the silver livery that was used on the Jubilee line until being withdrawn in 1996. These same trains are still in service on the Piccadilly Line (my favourite line!) but will be withdrawn soon, likely in 2025. In my opinion, the withdrawal of these trains is sad; not just because I like them so much, but because the replacements are so extraordinarily ugly - would it have been so hard to retain the characteristic curved windows of these trains which are so key to their charm? Anyway, the 1972 stock, despite being older, persist on the Bakerloo Line. these trains share the red and white and blue livery of the Piccadilly Line (and all other lines), as well as the distinctive windows and doors. The difference between these trains and many others is they retain the sprung seating of older rolling stock, such as the 1938 stock, making them much more comfortable than any other train. They also have a unique moquette, with the same London skyline pattern as others, but in unique colours. I love these trains so much, I hope someone with money buys one and keeps it at the railway centre I volunteer at - just for me :-)